The invention relates generally to local power range monitoring of nuclear reactors, and more specifically to use of a high dielectric insulated coax cable to achieve steady state local power level measurements for a reactor core.
One method of local power range monitoring (LPRM) of a boiling water reactor is based on a traversing incore probe (TIP) technique. FIG. 1 illustrates a boiling water reactor known in the art. One known LPRM method employs a neutron or gamma sensor on the end of a 200 foot helical drive cable to obtain a three dimensional power profile. The associated TIP insertion and withdrawal operations require significant maintenance, are subject to radiation contamination, suffer from slow data collection, require a large foot print, and undesirable spatial inaccuracies.
Another method of local power range monitoring of a boiling water reactor is based on a gamma thermometer for measuring temperature. The gamma thermometer technique however, has a lower accuracy than that associated with TIP techniques, has an unknown lifetime and high maintenance costs.
One proposed method of local power range monitoring of a boiling water reactor is directed to measurement of impedance changes of a mineral insulated coaxial cable that includes ionization of a filled inert gas in a loosely packed Al2O3 or MgO powder. The above proposed method is a newer concept utilizing coaxial cable with time domain reflectometry (TDR) techniques. Although this concept overcomes many of the disadvantages associated with TIP and gamma thermometer techniques known in the art, it still leaves room for increased spatial accuracy.
In view of the foregoing, it would be advantageous to provide a method of local power range monitoring of a boiling water reactor that avoids the above problems.